68Ga-FAPI PET/CT Imaging for Diagnosis, Grading, and Efficacy Evaluation of Myelofibrosis.

Inclusion Criteria: 1. Age ≥18 years old; 2. Cohort 1: Patients with suspected or confirmed myelofibrosis; Cohort 2: Patients with primary/secondary myelofibrosis who were not treated with ruxolitinib. 3. The expected survival time is over 3 months 4. Voluntarily sign informed consent. 5. Willing and able to follow the research protocol; 6. The subject must be able to lie on the scanning bed for 20 minutes; Exclusion Criteria: 1. Known allergic history to 68Ga FAPI or its excipients; 2. Patients who can not tolerate intravenous drug administration (such as needle fainting and blood fainting history); 3. Those who are not suitable for or unable to complete imaging tests such as PET due to special reasons, including claustrophobia and radiophobia; 4. pregnant and lactating women; 5. Workers who are exposed to radiation for a long period of time; 6. Serious diseases of the heart, kidney, lung, blood vessel, nervous system, mental system, immune deficiency diseases and hepatitis/cirrhosis; 7. Participating in other interventional clinical trials within 1 month before screening; 8. Patients undergoing chemotherapy, immunotherapy or molecular targeted therapy due to other cancers; 9. There are other circumstances that the researcher thinks are not suitable for participating in this study;